1. It is never a good idea to hand freed a Lionfish. No matter how tame you think your Lionfish to be, they still have very venomous spines and should never be hand fed.
2. When keeping aggressive species of fish, it is best not to introduce peaceful species of fish among them. Aggressive fish will tend to bully the more peaceful fish. Make sure to thoroughly read about the compatibility of the selected fish for the aquarium.
3. It is generally a good practice to purchase the largest aquarium that you can actually afford. A larger aquarium will be less susceptible to quick changes in the chemistry, and will offer much more stability.